Internal combustion engine



FIG. 1 is a top perspective view of an internal combustion engine showing our new design with the end of the exhaust pipe broken away for convenience of illustration;

FIG. 2 is a front perspective view thereof;

FIG. 3 is a bottom perspective view thereof;

FIG. 4 is a rear perspective view thereof;

FIG. 5 is a left side perspective view thereof, it being understood that the right side is substantially a mirror image of the left side shown herein; and

FIG. 6 is a top, front perspective view thereof. 

The ornamental design for an internal combustion engine, as shown. 